Re: [PATCH v12 2/5] soc: qcom: Add Sleep stats driver

Maulik Shah
2021-10-19T12:47:14Z

Hi Shawn,

On 10/19/2021 3:17 PM, Shawn Guo wrote:
> On Mon, Oct 18, 2021 at 07:45:30PM +0530, Maulik Shah wrote:
>>>> +static void qcom_create_soc_sleep_stat_files(struct dentry *root, void __iomem *reg,
>>>> + struct stats_data *d,
>>>> + const struct stats_config *config)
>>>> +{
>>>> + char stat_type[sizeof(u32) + 1] = {0};
>>>> + size_t stats_offset = config->stats_offset;
>>>> + u32 offset = 0, type;
>>>> + int i, j;
>>>> +
>>>> + /*
>>>> + * On RPM targets, stats offset location is dynamic and changes from target
>>>> + * to target and sometimes from build to build for same target.
>>>> + *
>>>> + * In such cases the dynamic address is present at 0x14 offset from base
>>>> + * address in devicetree. The last 16bits indicates the stats_offset.
>>>> + */
>>>> + if (config->dynamic_offset) {
>>>> + stats_offset = readl(reg + RPM_DYNAMIC_ADDR);
>>>> + stats_offset &= RPM_DYNAMIC_ADDR_MASK;
>>>> + }
>>>> +
>>>> + for (i = 0; i < config->num_records; i++) {
>>>> + d[i].base = reg + offset + stats_offset;
>>>> +
>>>> + /*
>>>> + * Read the low power mode name and create debugfs file for it.
>>>> + * The names read could be of below,
>>>> + * (may change depending on low power mode supported).
>>>> + * For rpmh-sleep-stats: "aosd", "cxsd" and "ddr".
>>>> + * For rpm-sleep-stats: "vmin" and "vlow".
>>>
>>> It reports 'vmin' and 'xosd' on MSM8939, 'vmin' and 'vlow' on SDM660.
>>> I know that 'vmin' is VDD Minimization mode, and 'xosd' is XO Shutdown
>>> mode. But I'm not sure about 'vlow' mode. Could you share some
>>> information regarding what this low power mode is, and how it differs
>>> from 'vmin' and 'xosd'?
>>
>> vlow and xosd are same.
>> vmin is xosd plus voltage minimization of chip, memory rails.
>
> Thanks much for the info, Maulik!
>
> I'm running your driver on qcm2290 and trying to reach vlow mode.
>
> # cat /sys/kernel/debug/qcom_sleep_stats/vlow
> Count: 0
> Last Entered At: 0
> Last Exited At: 0
> Accumulated Duration: 0
> Client Votes: 0x81
> # echo mem > /sys/power/state
> [ 551.446603] PM: suspend entry (s2idle)
> [ 551.450948] Filesystems sync: 0.000 seconds
> [ 551.462828] Freezing user space processes ... (elapsed 0.002 seconds) done.
> [ 551.472276] OOM killer disabled.
> [ 551.475556] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
> [ 551.484461] printk: Suspending console(s) (use no_console_suspend to debug)
> [ 551.561280] OOM killer enabled.
> [ 551.564461] Restarting tasks ... done.
> [ 551.569652] PM: suspend exit
> # cat /sys/kernel/debug/qcom_sleep_stats/vlow
> Count: 0
> Last Entered At: 0
> Last Exited At: 0
> Accumulated Duration: 0
> Client Votes: 0x818081
>
> The count doesn't increases along with suspend/resume cycle at the
> moment. But as you can see, 'Client Votes' field changes. If possible,
> could you shed some light on what this means?

The count will increase only when all the subsystems (APSS/Modem,etc)
are in power down mode and finally RPM decides to turn off xo clock.

>
> As the comparison, I'm also running the downstream 'rpm_master_stats'
> driver in the same kernel, and the 'xo_count' field of APSS does
> increase along with suspend/resume cycle. May I ask some advices what
> I'm possibly missing and thus getting different result between 'vlow'
> and 'rpm_master_stats' report?

The vlow is a SoC level state whereas the rpm master stats indicate
individual subsystem state. Since you are running suspend-resume the
APSS is going to sleep so you see xo_count incremented for it but for
MPSS i see it does not increase (modem is not entering to low power
mode). similarly for ADSP/CDSP it does not increment. if all of these
subsystems goes to power down and then there is sufficient sleep time
for the SoC then you may see vlow/vmin incrementing.

Hope this clarifies.

Thanks,
Maulik

>
> # cat /sys/kernel/debug/rpm_master_stats
> APSS
> shutdown_req:0x37EA3CC74
> wakeup_ind:0x0
> bringup_req:0x37F041958
> bringup_ack:0x37F042D54
> xo_last_entered_at:0x286FF36AC
> xo_last_exited_at:0x28AF94178
> xo_accumulated_duration:0x3EDD55B
> last_sleep_transition_duration:0x122f
> last_wake_transition_duration:0x11f8
> xo_count:0x1
> wakeup_reason:0x0
> numshutdowns:0x641
> active_cores:0x1
> core0
> MPSS
> shutdown_req:0x0
> wakeup_ind:0x0
> bringup_req:0x0
> bringup_ack:0x0
> xo_last_entered_at:0x0
> xo_last_exited_at:0x0
> xo_accumulated_duration:0x0
> last_sleep_transition_duration:0x0
> last_wake_transition_duration:0x0
> xo_count:0x0
> wakeup_reason:0x0
> numshutdowns:0x0
> active_cores:0x1
> core0
> ADSP
> shutdown_req:0x0
> wakeup_ind:0x0
> bringup_req:0x0
> bringup_ack:0x0
> xo_last_entered_at:0x0
> xo_last_exited_at:0x0
> xo_accumulated_duration:0x0
> last_sleep_transition_duration:0x0
> last_wake_transition_duration:0x0
> xo_count:0x0
> wakeup_reason:0x0
> numshutdowns:0x0
> active_cores:0x1
> core0
> CDSP
> shutdown_req:0x0
> wakeup_ind:0x0
> bringup_req:0x0
> bringup_ack:0x0
> xo_last_entered_at:0x0
> xo_last_exited_at:0x0
> xo_accumulated_duration:0x0
> last_sleep_transition_duration:0x0
> last_wake_transition_duration:0x0
> xo_count:0x0
> wakeup_reason:0x0
> numshutdowns:0x0
> active_cores:0x0
> TZ
> shutdown_req:0x0
> wakeup_ind:0x0
> bringup_req:0x0
> bringup_ack:0x0
> xo_last_entered_at:0x0
> xo_last_exited_at:0x0
> xo_accumulated_duration:0x0
> last_sleep_transition_duration:0x0
> last_wake_transition_duration:0x0
> xo_count:0x0
> wakeup_reason:0x0
> numshutdowns:0x0
> active_cores:0x0
>
> Any comment or suggestion would be much appreciated!
>
> Shawn
>

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